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                          Ground water quality in Kerala                               [Home]

 

Chemical Lab

The sampling and analysis of National Hydrograph Stations evaluates the quality of shallow ground water in Kerala State.  221 and 217 NH stations were monitored in April, 2002 and January 2003 respectively.  An Electrical conductivity value of less than 1000 us/cm at 25oc C in about 95% of the NH station indicates fresh ground water.  An EC value of 1000 to 3000 us/cm at 25o C indicates slightly mineralized ground water in about 5% of the NH station.  These are small pockets in the districts of Ernakulam, Kollam, Palakkad and Trivandrum.  The fluoride content is less than 1 mg/l for about 98% of the sample analysed from National Hydrograph Network Stations and 2% of sample shows 1.0 – 1.5 mg/l which are from Palakkad district.

Drinking water standard

Depending on the impact of concentration of various ions in water on human health various standards have been laid down by the different agencies.  These standards are useful for deciding the suitability of water for drinking purpose.  The drinking water standards laid down by Bureau of Indian Standards (BIS), Indian Council of Medical Research (ICMR) has been given below:

Drinking water standards:

    Prescribed by
Sl.No. Parameters BIS (IS 10500-91) ICMR
    Desirable Limit Max. permissible Limits in the absence of alternate source Desirable Limit Max. permissible limits
1 2 3 4 5 6
1 PH 6.5 to8.5 No relaxation 7.0 – 8.5 6.5 – 9.2
2 Total dissolved solids mg/L 500 2000 500 1500-3000
3 Total hardness as CaCO3 mg/L 300 600 300 600
4 Calcium as Ca mg/L 75 200 75 200
5 Magnesium as Mg mg/L 30 100 50 -
6 Chloride as Cl mg/L 250 1000 200 1000
7 Sulphate as SO4 mg/L 200 400 200 400
8 Nitrate as NO3 mg/L 45 100 20 100
9 Iron as Fe mg/L 0.3 1 0.1 1
10 Fluoride as F mg/L 1 1.5 1 1.5
11 Arsenic as As mg/L 0.05 0.05 - 0.05
12 Manganese as Mn mg/L 0.1 0.3 0.1 0.5
13 Zinc as Zn mg/L 5 15 0.1 5
14 Copper as Cu mg/L 0.05 1.5 0.05 1.5
15 Chromium as Cr mg/L 0.05 0.05 - -
16 Lead as Pb mg/L 0.05 0.05 - 0.5
17 Mercury as Hg mg/L 0.001 0.001 - 0.001
18 Cadmium as Cd mg/L 0.01 0.01 - 0.01
19 Cyanide as CN mg/L 0.05 0.05 - 0.05
20 Minerals Oil mg/L 0.01 0.03 - -
21 Phenolic compounds mg/L 0.001 0.002 - -
22 Total Coliform MPN/100 ml 1 10 - -
23 Residual free chlorine mg/L 0.2 - - -
24 Aluminium as A1 mg/L 0.03 0.2    
25 Boron as B mg/L 1 5    
26 Selenium as Se mg/L 0.01 -    
27 Pesticides Absent 0.001    
Ground Water Quality
Regional Director, Central Ground Water Board, Ministry of Water Resources, Kerala Region,
Kedaram, Kesavadasapuram, Trivandrum - 695 004
Phone: 0471-2442175 , 2440688      e-mail: cgwtvm@sify.com     TeleFax: 0471-2442191
 
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Last modified: 11/05/04